Percutaneous Radiofrequency Ablation of Hepatocellular Carcinoma against the Diaphragm: Is Artificial Ascites Necessary?

Purpose: To evaluate the utility of artificial ascites induction for radiofrequency ablation (RFA) of peridiaphragmatic hepatocellular carcinoma (HCC) through retrospective cohort analysis comparing characteristics and complications of peridiaphragmatic HCC without the use of artificial ascites to non-peridiaphragmatic HCC. Materials and Methods: IRB approval was obtained. From September 2003 to December 2008, 150 consecutive patients with hepatic tumors received percutaneous RFA. 110 patients had presumed HCC, and of those 21 had lesions abutting the diaphragm. Of the remaining 89 patients with non-peridiaphragmatic HCC lesions, 21 were randomly selected for the comparison group. RFA volume, major and minor complication rates, pain, technical success, and recurrence rates were compared between the two groups. Results: There was no statistical difference in RFA volume (P = 0.962), overall major complication rate (P = 0.343) and minor complication rate (P = 0.118) between the two groups. However, the peridiaphragmatic group that underwent RFA with a clustered-needle demonstrated a statistically significant higher proportion of major complications compared to the non-peridiaphragmatic clustered-needle group (P = 0.033). There was no statistical difference in pain severity (P = 0.8802) or pain location (P = 0.15). There was no statistical difference in technical success rates (P = 1), local tumor progression rates (P = 1), or time to local tumor recurrence (P = 0.67). Conclusion: Artificial ascites induction for RFA of HCC lesions adjacent to the diaphragm may not be necessary, although clustered electrode technique should be avoided in this location as they present with a higher complication rate.